Semiconductor integrated circuit mountable on recording device and method of operating the same

ABSTRACT

A semiconductor integrated circuit has a video encoder including a motion prediction unit, a motion compensation unit, a subtraction unit, a discrete cosine transform unit, a quantization unit, an inverse quantization unit, an inverse discrete cosine transform unit, and an addition unit. The encoder divides the video signal from the camera into a plurality of partial images including the central part of the image and the peripheral part of the image according to the distance from the center of the image, and processes the partial images. A pixel processing unit coordinate-transforms coordinates of a pixel included in the central part of the image into coordinates of the peripheral part of the image, and performs a process of enlarging an object of a subject included in the central part of the image on a pixel-by-pixel basis when performing the coordinate transform.

CROSS-REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Application No. 2011-9474 filed onJan. 20, 2011 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to a semiconductor integrated circuitwhich is mountable on a recording device such as a drive recorder and amethod of operating the same, and particularly to a technology which iseffective to reduce the processing load and power consumption whenrecording video images of a large number of subjects moving fromgenerally the center of the image toward the peripheral part of theimage.

Conventionally, when an accident of a vehicle such as an automobileoccurs, it is not rare that a dispute with regard to fact findingassociated with the accident arises among the parties concerned. Itoften happens that allegations of the parties concerned conflict as towhether the traffic signal was green or red, or whether there was asudden dash.

An aircraft, in contrast, has mounted thereon a driving situationrecording device called a flight recorder, and data of the recordeddriving situation is used as important evidence when investigating thecause of an aircraft accident.

Accordingly, as with the flight recorder equipped in an aircraft, therehas been proposed a drive recorder also for a vehicle such as anautomobile, which records a few dozen seconds long video before andafter an accident occurs, in place of an eyewitness at the time of theaccident.

For example, the drive recorder records digital video signals anddigital audio signals as drive recorder information respectively outputfrom a vehicle-mounted camera and a vehicle-mounted microphone to a harddisk drive (HDD) of a vehicle-mounted recording medium.

The following patent document 1 (Japanese Patent Laid-Open No.2005-323021) describes, for a vehicle-mounted imaging system whichcaptures images of a subject in front of the running direction while thevehicle is running in which an object included generally in the centerof an image captured at the current capture timing appears at the nextcapture timing as an enlarged object that has been moved toward theperipheral part of the image, detecting an optical flow of thestationary subject using the moving speed of the vehicle detected by avehicle speed detecting unit, moving respective objects included in theimages captured by the imaging system using the optical flow, andcompressing the images by calculating the difference between the imagein which the object has been moved and the image in the next frame.

The vehicle-mounted imaging system described in the following patentdocument 1 includes a characteristic point extraction unit and anpositioning unit so that the characteristic point extraction unitextracts a characteristic point of the image in which the object hasbeen moved and a characteristic point of the image in the next frame,and the positioning unit moves the object again in order to position thecharacteristic points, extracted by the characteristic point extractionunit, of the image in which the object has been moved. Included in thecharacteristic points extracted by the characteristic point extractionunit are: edges, particular straight lines and curves, particularshapes, or regions having particular colors.

SUMMARY

Before making the present invention, the inventors had been engaged indevelopment of a semiconductor integrated circuit which is mountable ona drive recorder.

Before making the present invention, the inventors had examined indetail the vehicle-mounted imaging system described in the patentdocument 1. As a result of the examination by the inventors, a problemhas been revealed that, since characteristic point extraction by thecharacteristic point extraction unit is required to perform imagecompression in the vehicle-mounted imaging system described in thepatent document 1, the processing load and power consumption of thevehicle-mounted imaging system are large for extracting characteristicpoints of objects of all the stationary subjects moving from generallythe center of the image toward the peripheral part of the image.

The present invention has been made as a result of the examination bythe inventors prior to the present invention as described above.

Therefore, it is a purpose of the present invention to reduce theprocessing load and power consumption when recording video images of alarge number of subjects moving from generally the center of the imagetoward the peripheral part of the image.

The other purposes and the new feature of the present invention willbecome clear from the description of the present specification and theaccompanying drawings.

The following explains briefly the outline of a typical invention amongthe inventions disclosed in the present application.

A semiconductor integrated circuit (ENC) according to a representativeembodiment of the present invention has a video encoder including amotion prediction unit (2), a motion compensation unit (4), asubtraction unit (3), a discrete cosine transform unit (51), aquantization unit (52), an inverse quantization unit (61), an inversediscrete cosine transform unit (62), and an addition unit (63).

The video encoder divides the video signal from the camera into aplurality of partial images including the central part of the image andthe peripheral part of the image according to the distance from thecenter of the image, and processes the partial images.

The video encoder further includes a pixel processing unit (64)connected between the output of the addition unit and the other input ofthe motion compensation unit.

The pixel processing unit coordinate-transforms coordinates of a pixelincluded in the central part of the image in the reference image of theoutput of the addition unit into coordinates of the peripheral part ofthe image.

The pixel processing unit is characterized by performing a process ofenlarging an object of a subject included in the central part of theimage on a pixel-by-pixel basis when performing the coordinate transform(see FIGS. 1 and 2).

The following explains briefly the effect acquired by the typicalinvention among the inventions disclosed in the present application.

According to the present invention, the processing load and powerconsumption can be reduced when recording video images of a large numberof subjects moving from generally the center of the image toward theperipheral part of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration of a semiconductor integrated circuitENC which is mountable on a drive recorder according to an embodiment 1of the present invention;

FIG. 2 illustrates how a large number of subjects move from generallythe center of the image toward the peripheral part of the image whencapturing video images in front of the vehicle with a vehicle frontcamera of a drive recorder having mounted thereon the semiconductorintegrated circuit ENC according to the embodiment 1 of the presentinvention shown in FIG. 1;

FIG. 3 illustrates how a reference image is generated for the next framefrom a image captured at the current timing when the video in front ofthe vehicle is captured by the vehicle-mounted front camera of the driverecorder having mounted thereon the semiconductor integrated circuit ENCaccording to the embodiment 1 of the present invention shown in FIG. 1;

FIG. 4 illustrates the captured image in front of the vehicle at thenext timing of the current timing when the image shown in FIG. 3 iscaptured;

FIG. 5 is an explanatory diagram of a hierarchical structure to a blockfrom a sequence of an encoding process by the video encoding processperformed by the semiconductor integrated circuit ENC which is mountableon the drive recorder according to the embodiment 1 of the presentinvention shown in FIG. 1;

FIG. 6 illustrates how the size of an object of a subject is enlargedand reduced on a pixel-by-pixel basis by a pixel enlargement/reductionunit 64 of a local decoding unit 6 of the semiconductor integratedcircuit ENC which is mountable on the drive recorder according to theembodiment 1 of the present invention shown in FIG. 1;

FIG. 7 illustrates a configuration of another semiconductor integratedcircuit ENC which is mountable on a drive recorder according to anembodiment 2 of the present invention; and

FIG. 8 illustrates how an image of a stationary subject (backgroundimage) is captured, together with an oncoming vehicle and a passingvehicle, when capturing video images in front of the vehicle by thevehicle front camera of the drive recorder having mounted thereon thesemiconductor integrated circuit ENC according to the embodiment 2 ofthe present invention shown in FIG. 7.

DETAILED DESCRIPTION 1. Outline of Embodiments

First, representative embodiments of the invention disclosed in theapplication will be described. Reference numerals in the drawings,referred to with parentheses in the outline explanation ofrepresentative embodiments, are only illustrative of what is included inthe spirit of the components to which the numerals are provided.

[1] A semiconductor integrated circuit (ENC) according to arepresentative embodiment of the present invention has a video encoderincluding a motion prediction unit (2), a motion compensation unit (4),a subtraction unit (3), a discrete cosine transform unit (51), aquantization unit (52), an inverse quantization unit (61), an inversediscrete cosine transform unit (62), and an addition unit (63).

The motion prediction unit generates, in response to a video signal froma camera, a motion vector from the video signal, and the motionprediction unit supplies the motion vector to one input of the motioncompensation unit.

The video signal from the camera can be supplied to one input of thesubtraction unit, the output of the subtraction unit can be supplied tothe input of the discrete cosine transform unit, the output of thediscrete cosine transform unit can be supplied to the input of thequantization unit, the output of the quantization unit can be suppliedto the input of the inverse quantization unit, the output of the inversequantization unit can be supplied to the input of the inverse discretecosine transform unit, the output of the inverse discrete cosinetransform unit can be supplied to one input of the addition unit, areference image of the output of the addition unit can be supplied tothe other input of the motion compensation unit, and a motioncompensation prediction signal of the output of the motion compensationunit can be supplied to the other input of the subtraction unit and theother input of the addition unit.

The video encoder divides the video signal from the camera into aplurality of partial images including the central part of the image andthe peripheral part of the image according to the distance from thecenter of the image, and processes the partial images.

The video encoder further includes a pixel processing unit (64)connected between the output of the addition unit and the other input ofthe motion compensation unit.

The pixel processing unit coordinate-transforms coordinates of a pixelincluded in the central part of the image in the reference image of theoutput of the addition unit into coordinates of the peripheral part ofthe image.

The pixel processing unit is characterized by performing a process ofenlarging an object of a subject included in the central part of theimage on a pixel-by-pixel basis when performing the coordinate transform(see FIGS. 1 and 2).

According to the embodiment, the processing load and power consumptioncan be reduced when recording video images of a large number of subjectsmoving from generally the center of the image toward the peripheral partof the image.

In a preferred embodiment, the camera is a vehicle front camera whichcaptures video images in front of the vehicle.

It is characterized in that the amount of movement of the pixel due tothe coordinate transform of the pixel from the central part of the imagetoward the peripheral part of the image, and the enlargement factor ofthe object of the subject moving from the central part of the image tothe peripheral part of the image are calculated by the pixel processingunit which responds to vehicle speed information from a vehicle speedmeasurement unit mounted on the vehicle (see FIGS. 3 to 6).

In another preferred embodiment, the video encoder is characterized bydividing the video signal from the camera into the central part of theimage, the peripheral part of the image, and an intermediate part of theimage between the central part and the peripheral part, and processingthe respective parts (see FIGS. 2, 3, and 4).

In still another preferred embodiment, the video encoder ischaracterized by further including a first memory (1) connected to theone input of the subtraction unit and the input of the motion predictionunit to store the video signal from the camera, and a second memory (65)connected between the output of the pixel processing unit and the otherinput of the motion compensation unit to store an output image signal ofthe pixel processing unit (see FIG. 1).

In a more preferred embodiment, the video encoder further includes afirst variable-length encoding unit (53), a second variable-lengthencoding unit (7), and a buffer unit (8).

The output of the quantization unit can be supplied to the input of thefirst variable-length encoding unit, and the motion vector generated bythe motion prediction unit can be supplied to the input of the secondvariable-length encoding unit.

It is characteristic in that the output of the first variable-lengthencoding unit and the output of the second variable-length encoding unitcan be supplied to one input and the other input of the buffer unit,respectively, and in that the output of the buffer unit can be recordedon a recording medium (see FIG. 1).

In a specific embodiment, the video encoder includes a first videoencoder (B-ENC) and a second video encoder (OB-ENC).

The first video encoder processes an object of a stationary subject,which is the subject moving from the central part of the image towardthe peripheral part of the image.

The second video encoder is characterized by processing an object of amoving subject, which is the subject moving from the central part of theimage toward the peripheral part of the image (see FIG. 7).

In a more specific embodiment, the semiconductor integrated circuit ischaracterized by further including an image synthesizing unit (9) whichsynthesizes a first video encoded signal generated by the first videoencoder and a second video encoded signal generated by the second videoencoder (see FIG. 7).

In the most specific embodiment, the output of the image synthesizingunit (9) is characterized by being recordable on a recording medium (seeFIG. 7).

[2] A representative embodiment of the present invention from anotherviewpoint is a method of operating the semiconductor integrated circuit(ENC) having the video encoder including the motion prediction unit (2),the motion compensation unit (4), the subtraction unit (3), the discretecosine transform unit (51), the quantization unit (52), the inversequantization unit (61), the inverse discrete cosine transform unit (62),and the addition unit (63).

The motion prediction unit generates, in response to the video signalfrom the camera, a motion vector from the video signal, and the motionprediction unit supplies the motion vector to one input of the motioncompensation unit.

The video signal from the camera can be supplied to one input of thesubtraction unit, the output of the subtraction unit can be supplied tothe input of the discrete cosine transform unit, the output of thediscrete cosine transform unit can be supplied to the input of thequantization unit, the output of the quantization unit can be suppliedto the input of the inverse quantization unit, the output of the inversequantization unit can be supplied to the input of the inverse discretecosine transform unit, the output of the inverse discrete cosinetransform unit can be supplied to one input of the addition unit, areference image of the output of the addition unit can be supplied tothe other input of the motion compensation unit, a motion compensationprediction signal of the output of the motion compensation unit can besupplied to the other input of the subtraction unit and the other inputof the addition unit.

The video encoder divides the video signal from the camera into aplurality of partial images including the central part of the image andthe peripheral part of the image according to the distance from thecenter of the image, and processes the partial images.

The video encoder further includes the pixel processing unit (64)connected between the output of the addition unit and the other input ofthe motion compensation unit.

The pixel processing unit coordinate-transforms coordinates of a pixelincluded in the central part of the image in the reference image of theoutput of the addition unit into coordinates of the peripheral part ofthe image.

The pixel processing unit is characterized by performing a process ofenlarging an object of a subject included in the central part of theimage on a pixel-by-pixel basis when performing the coordinate transform(see FIGS. 1 and 2).

According to the embodiment, the processing load and power consumptioncan be reduced when recording video images of a large number of subjectsmoving from generally the center of the image toward the peripheral partof the image.

2. Details of Embodiments

Next, the embodiments will be described in more detail. In all thedrawings for explaining the best embodiments, the same symbol isattached to the same member, as a principle, and the repeatedexplanation thereof is omitted.

Embodiment 1 Configuration of Semiconductor Integrated Circuit Mountableon Drive Recorder

FIG. 1 illustrates a configuration of a semiconductor integrated circuitENC which is mountable on a drive recorder according to an embodiment 1of the present invention.

The semiconductor integrated circuit ENC which is mountable on the driverecorder according to the embodiment 1 of the present invention shown inFIG. 1 includes a first frame memory 1, a motion prediction unit 2, asubtraction unit 3, a motion compensation unit 4, a residual encodingunit 5, a local decoding unit 6, a motion vector variable-lengthencoding unit 7, and a buffer unit 8.

The residual encoding unit 5 includes a discrete cosine transform unit(DCT) 51, a quantization unit (Q) 52, and a residual variable-lengthencoding unit 53, and the local decoding unit 6 includes an inversequantization unit (IQ) 61, an inverse discrete cosine transform unit(IDCT) 62, an addition unit (+) 63, a pixel enlargement/reduction unit64, and a second frame memory 65.

A video signal Video_in from a vehicle front camera which captures videoimages in front of the vehicle such as an automobile is stored withinthe first frame memory 1 of the semiconductor integrated circuit ENC.The motion prediction unit 2 generates a motion vector MV from the videosignal Video_in stored in the first frame memory 1, and the motionvector MV is supplied to the motion compensation unit 4 and the motionvector variable-length encoding unit 7. While the video signal beingread from the first frame memory 1 according to the encoding order issupplied to one input terminal of the subtraction unit 3, a compensationprediction signal is supplied from the motion compensation unit 4 to theother input terminal of the subtraction unit 3, so that a predictedresidual generated from the output of the subtraction unit 3 is suppliedto the residual encoding unit 5.

In the residual encoding unit 5, the predicted residual from the outputof the subtraction unit 3 is quantized by the quantization unit (Q) 52,after having been subjected to discrete cosine transform, which is anorthogonal transform, by the discrete cosine transform unit (DCT) 51.The quantized residual signal of the quantization unit (Q) 52 of theresidual encoding unit 5 is encoded by the residual variable-lengthencoding unit 53, and the residual variable-length encoding signalgenerated from the residual variable-length encoding unit 53 is suppliedto one input terminal of the buffer unit 8. In addition, the quantizedresidual signal of the quantization unit 52 of the residual encodingunit 5 is subjected to inverse discrete cosine transform by the inversediscrete cosine transform unit (IDCT) 62, after having been subjected toinverse quantization by the inverse quantization unit (IQ) 61 of thelocal decoding unit 6. While the inverse discrete cosine residual signalof the inverse discrete cosine transform unit (IDCT) 62 is supplied toone input terminal of the addition unit (+) 63, a motion compensationprediction signal from the motion compensation unit 4 is supplied to theother input terminal of addition unit (+) 63, so that the referenceimage generated from the output of addition unit (+) 63 is stored in thesecond frame memory 65 via the pixel enlargement/reduction unit 64.Therefore, the motion compensation unit 4 generates a motioncompensation prediction signal from the reference image stored in thesecond frame memory 65 and the motion vector MV supplied from the motionprediction unit 2. In addition, supplying the motion vector MV generatedby the motion prediction unit 2 to the motion vector variable-lengthencoding unit 7 causes the motion vector variable-length encoding unit 7to generate a motion vector variable-length encoded signal, which isthen supplied to the other input terminal of the buffer unit 8.Therefore, a video compression bit stream BS is generated from theoutput terminal of the buffer unit 8, and the video compression bitstream BS is recorded in a vehicle-mounted recording medium including ahard disk drive (HDD) or a semiconductor nonvolatile memory, which arenot shown in FIG. 1.

The configuration of the semiconductor integrated circuit ENC which ismountable on the drive recorder according to the embodiment 1 of thepresent invention shown in FIG. 1 is identical to the configuration ofthe well-known MPEG (Moving Picture Experts Group) video encoder exceptfor the pixel enlargement/reduction unit 64 of the local decoding unit6.

<<Outline of Video Encoding Operation by Semiconductor IntegratedCircuit>>

The semiconductor integrated circuit ENC according to the embodiment 1of the present invention shown in FIG. 1 divides a video signal from avehicle front camera which captures video images in front of the vehiclesuch as an automobile into a plurality of partial images including thecentral part of the image and the peripheral part of the image accordingto the distance from the center of the image. In order to generate aperipheral reference image for the peripheral part of the image from thecaptured central image of the central part of the image, a centralreference image is generated from the captured central image, byprocessing the captured central image respectively by the discretecosine transform unit (DCT) 51, the quantization unit (Q) 52, theinverse quantization unit (IQ) 61, and the inverse discrete cosinetransform unit (IDCT) 62.

The pixel enlargement/reduction unit 64 of the semiconductor integratedcircuit ENC transforms coordinates of a pixel included in the centralreference image to coordinates of a peripheral part of the image inorder to move the central reference image toward the peripheral part ofthe image, and also performs a process of enlarging an object of asubject included in the central reference image on a pixel-by-pixelbasis. The amount of movement of pixels due to coordinate transform ofthe pixel from the central part of the image toward the peripheral partof the image and the enlargement factor of the object of the subjectmoving from the central part of the image toward the peripheral part theimage are calculated by the pixel enlargement/reduction unit 64 whichresponds to the vehicle speed information of the vehicle speedmeasurement unit.

<<Pixel Enlargement/Reduction Unit>>

The pixel enlargement/reduction unit 64 of the local decoding unit 6 ofthe semiconductor integrated circuit ENC which is mountable on the driverecorder according to the embodiment 1 of the present invention shown inFIG. 1 is provided particularly in the semiconductor integrated circuitENC in order to reduce the processing load and power consumption whenrecording video images of a large number of subjects moving fromgenerally the center of the image toward the peripheral part of theimage captured by the vehicle front camera which captures video imagesin front of the vehicle such as an automobile. In addition, the pixelenlargement/reduction unit 64 has vehicle speed information suppliedthereto from the vehicle speed measurement unit such as a speedometer ofan automobile or the like.

The pixel enlargement/reduction unit 64 performs a pixel enlargementprocess when the vehicle-mounted camera is a vehicle front camera,whereas the pixel enlargement/reduction unit 64 performs a pixelreduction process when the vehicle-mounted camera is a vehicle rearcamera which captures video images behind the vehicle. When capturing animage of a subject behind the running direction by the vehicle rearcamera while the vehicle is running, an object of the peripheral part ofthe image captured at the current capture timing appears as a reducedobject that has moved to generally the center at the next capturetiming, and thus a pixel reduction process by the pixelenlargement/reduction unit 64 is required.

Therefore, when the vehicle-mounted camera is mounted on the vehicle asa front camera, the operation mode is set so that the pixelenlargement/reduction unit 64 of the local decoding unit 6 performs apixel enlargement process. On the contrary, when the vehicle-mountedcamera is mounted on the vehicle as a rear camera, the operation mode isset so that the pixel enlargement/reduction unit 64 of the localdecoding unit 6 performs a pixel reduction process.

<<Image of Vehicle Front Camera>>

FIG. 2 illustrates how a large number of subjects move from generallythe center of the image toward the peripheral part of the image whenvideo images in front of the vehicle are captured by the vehicle frontcamera of the drive recorder having mounted thereon the semiconductorintegrated circuit ENC according to the embodiment 1 of the presentinvention shown in FIG. 1.

As shown in FIG. 2, the size of an object of a subject in a central partLc of the image is small, the object of the subject then becomes mediumsized in an intermediate part Lm of the image, and the object of thesubject is enlarged to a big size in a peripheral part Lp of the image.In other words, although the high-rise building on the left-hand side ofthe road shown in FIG. 2 is a small-sized object Bc in the central partLc of the image, it becomes a large-sized object Bp in the peripheralpart Lp of the image. Furthermore, the low-rise house on the right-handside of the road shown in FIG. 2 is a small-sized object Hc in thecentral part Lc of the image, it becomes a large-sized object Hp in theperipheral part Lp of the image.

Therefore, in order to realize a high image compression rate whencapturing video images in front of the vehicle by the vehicle frontcamera of the drive recorder, it is necessary to enlarge the size of theobject of the reference image stored in the second frame memory 65 whenthe object of the subject is moving from the central part Lc of theimage to the intermediate part Lm of the image and further toward theperipheral part Lp of the image.

<<Generation of Reference Image>>

FIG. 3 illustrates how the reference image for the next frame isgenerated from the image captured at the current timing by capturingvideo images in front of the vehicle with the vehicle front camera ofthe drive recorder having mounted thereon the semiconductor integratedcircuit ENC according to the embodiment 1 of the present invention shownin FIG. 1.

As shown in FIG. 3, an image of one frame is divided into a firstpartial image which is the central part Lc of the image, a secondpartial image which is the intermediate part Lm of the image, and athird partial image which is the peripheral part Lp of the image.

First, the central part Lc of the image which is the first partial imageincludes pixels in the range of X pixel coordinates Xc1 to Xc2 andY-system pixel coordinates Yc1 to Yc2. Next, the intermediate part Lm ofthe image which is the second partial image includes pixels in the rangeof X-system pixel coordinates Xm1 to Xm2 and Y-system pixel coordinatesYm1 to Ym2 other than the central part Lc of the image which is thefirst partial image. Finally, the peripheral part Lp of the image whichis the third partial image includes pixels in the range of X-systempixel coordinates Xp1 to Xp2 and Y-system pixel coordinates Yp1 to Yp2other than the intermediate part Lm of the image which is the secondpartial image.

As for the image captured at the current timing, the central part Lc ofthe image which is the first partial image includes pixels of a thirdobject C of a subject located at a long distance from the vehicle front,the intermediate part Lm of the image which is the second partial imageincludes pixels of a second object B of a subject located at anintermediate distance from the vehicle front, and the peripheral part Lpof the image which is the third partial image includes pixels of a firstobject A of a subject located at a short distance from the vehiclefront.

FIG. 4 illustrates an image in front of the vehicle captured at thetiming next to the current timing when the image shown in FIG. 3 wascaptured.

Since the captured image shown in FIG. 4 no longer includes pixels ofthe first object A of the subject and the pixels of the first object Aof the subject have moved outside the captured image shown in FIG. 4,they have disappeared from the captured image of FIG. 4. Instead, pixelsof the second object B of the subject that were present in theintermediate part Lm of the image which is the second partial image ofFIG. 3 have moved toward the peripheral part Lp of the image which isthe third partial image of FIG. 4. Furthermore, pixels of the thirdobject C of the subject that were present in the central part Lc of theimage which is the first partial image of FIG. 3 have moved to theintermediate part Lm of the image which is the second partial image ofFIG. 4. Moreover, pixels of a fourth object D of a new subject that wasnot present in the captured image shown in FIG. 3 have appeared in thecentral part Lc of the image which is the first partial image of FIG. 4.

In FIGS. 3 and 4, the number of pixels in the X-direction and the numberof pixels in the Y-direct ion of the peripheral part Lp of the imagewhich is the third partial image are set to 1920 pixels×1080 pixels,which is the HD (High Definition) size having a high precision, forexample.

In FIGS. 3 and 4, the number of pixels in the X-direction and the numberof pixels in the Y-direction of the central part Lc of the image whichis the small-sized first partial image can be set to an arbitrary value,for example. However, in FIGS. 3 and 4, the enlargement factor of thenumber of pixels from the number of pixels in the X-direction and thenumber of pixels in the Y-direction of the central part Lc of the imagewhich is the small-sized first partial image to the number of pixels inthe X-direction and the number of pixels in the Y-direction of theintermediate part Lm of the image which is the intermediate-sized secondpartial image is determined by vehicle speed information from thevehicle speed measurement unit such as a speedometer of an automobile orthe like supplied to the pixel enlargement/reduction unit 64.

<<Coordinate Transform of Pixels>>

Therefore, it is necessary to move the third object C of the subject asan object of the reference image included in the central part Lc of theimage which is the first partial image of the captured image of FIG. 3to the intermediate part Lm which is the second partial image in orderto perform image compression of the third object C of the subject movingto the intermediate part Lm of the image which is the second partialimage of FIG. 4 with a high image compression rate. Accordingly,coordinates of respective pixels of the central part Lc of the imagewhich is the first partial image of the captured image of FIG. 3 aretransformed in particular. In other words, as shown by the arrows in thecentral part Lc of the image which is the first partial image of thecaptured image of FIG. 3, coordinates of respective pixels aretransformed so that particularly respective pixels inside the centralpart Lc of the image move to the intermediate part Lm of the image. Forexample, coordinates of pixels having the X-system pixel coordinates Xc1and the Y-system pixel coordinates Yc1 existing inside the central partLc of the image are transformed into coordinates of pixels having theX-system pixel coordinates Xm1 and the Y-system pixel coordinates Ym1.In addition, coordinates of pixels having the X-system pixel coordinates(Xc1+Xc2)/2 and the Y-system pixel coordinates Yc1 existing inside thecentral part Lc of the image are transformed into coordinates of pixelshaving the X-system pixel coordinates (Xm1+Xm2)/2 and the Y-system pixelcoordinates Ym1. In addition, coordinates of pixels having the X-systempixel coordinates Xc2 and the Y-system pixel coordinates Yc1 existinginside the central part Lc of the image are transformed into coordinatesof pixels having the X-system pixel coordinates Xm2 and the Y-systempixel coordinates Ym1. Coordinates of pixels having the X-system pixelcoordinates Xc2 and the Y-system pixel coordinates (Yc1+Yc2)/2 existinginside the central part Lc of the image are transformed into coordinatesof pixels having the X-system pixel coordinates Xm2 and the Y-systempixel coordinates (Ym1+Ym2)/2. In addition, coordinates of pixels havingthe X-system pixel coordinates Xc2 and the Y-system pixel coordinatesYc2 existing inside the central part Lc of the image are transformedinto coordinates of pixels having the X-system pixel coordinates Xm2 andthe Y-system pixel coordinates Ym2. In addition, coordinates of pixelshaving the X-system pixel coordinates (Xc1+Xc2)/2 and the Y-system pixelcoordinates Yc2 existing inside the central part Lc of the image aretransformed into coordinates of pixels having the X-system pixelcoordinates (Xm1+Xm2)/2 and the Y-system pixel coordinates Ym2. Inaddition, coordinates of pixels having the X-system pixel coordinatesXc1 and the Y-system pixel coordinates Yc2 existing inside the centralpart Lc of the image are transformed into coordinates of pixels havingthe X-system pixel coordinates Xm1 and the Y-system pixel coordinatesYm2. Finally, coordinate of pixels having the X-system pixel coordinatesXc1 and the Y-system pixel coordinates (Yc1+Yc2)/2 existing inside thecentral part Lc of the image are transformed into coordinates of pixelshaving the X-system pixel coordinates Xm1 and the Y-system pixelcoordinates (Ym1+Ym2)/2.

Particularly, in the semiconductor integrated circuit ENC which ismountable on the drive recorder according to the embodiment 1 of thepresent invention shown in FIG. 1, the above-mentioned coordinatetransform of all the pixels from the central part Lc of the image whichis the first partial image of the captured image into the intermediatepart Lm of the image which is the second partial image is automaticallyperformed by the pixel enlargement/reduction unit 64 in response to thevehicle speed information of the vehicle speed measurement unit.

It is necessary to move the third object C of the subject as an objectof the reference image included in the intermediate part Lm of the imagewhich is the second partial image of the captured image of FIG. 4 towardthe peripheral part Lp of the image which is the third partial image inorder to perform image compression of the third object C of the subjectmoving toward the peripheral part Lp of the image which is the thirdpartial image at the next capture timing of the capture timing shown inFIG. 4 with a high image compression rate. Accordingly, coordinates ofrespective pixels of the intermediate part Lm of the image which is thesecond partial image of the captured image of FIG. 4 are transformed inparticular. In other words, as shown by the arrows in the intermediatepart Lm of the image which is the second partial image of the capturedimage of FIG. 4, coordinates of respective pixels are transformed sothat particularly respective pixels inside the intermediate part Lm ofthe image move toward the peripheral part Lp of the image. For example,coordinates of pixels having the X-system pixel coordinates Xm1 and theY-system pixel coordinates Ym1 existing inside the intermediate part Lmof the image are transformed into coordinates of pixels having theX-system pixel coordinates Xp1 and the Y-system pixel coordinates Yp1.In addition, coordinates of pixels having the X-system pixel coordinates(Xm1+Xm2)/2 and the Y-system pixel coordinates Ym1 existing inside theintermediate part Lm of the image are transformed into coordinates ofpixels having the X-system pixel coordinates (Xp1+Xp2)/2 and theY-system pixel coordinates Yp1. In addition, coordinates of pixelshaving the X-system pixel coordinates Xm2 and the Y-system pixelcoordinates Ym1 existing inside the intermediate part Lm of the imageare transformed into coordinates of pixels having the X-system pixelcoordinates Xp2 and the Y-system pixel coordinates Yp1. Coordinates ofpixels having the X-system pixel coordinates Xm2 and the Y-system pixelcoordinates (Ym1+Ym2)/2 existing inside the intermediate part Lm of theimage are transformed into coordinates of pixels having the X-systempixel coordinates Xp2 and the Y-system pixel coordinates (Yp1+Yp2)/2. Inaddition, coordinates of pixels having the X-system pixel coordinatesXm2 and the Y-system pixel coordinates Ym2 existing inside theintermediate part Lm of the image are transformed into coordinates ofpixels having the X-system pixel coordinates Xp2 and the Y-system pixelcoordinates Yp2. In addition, coordinates of pixels having the X-systempixel coordinates (Xm1+Xm2)/2 and the Y-system pixel coordinates Ym2existing inside the intermediate part Lm of the image are transformedinto coordinates of pixels having the X-system pixel coordinates(Xp1+Xp2)/2 and the Y-system pixel coordinates Yp2. In addition,coordinates of pixels having the X-system pixel coordinates Xm1 and theY-system pixel coordinates Ym2 existing inside the intermediate part Lmof the image are transformed into coordinates of pixels having theX-system pixel coordinates Xp1 and the Y-system pixel coordinates Yp2.Finally, coordinates of pixels having the X-system pixel coordinates Xm1and the Y-system pixel coordinates (Ym1+Ym2)/2 existing inside theintermediate part Lm of the image are transformed into coordinates ofpixels having the X-system pixel coordinates Xp1 and the Y-system pixelcoordinates (Yp1+Yp2)/2.

Furthermore, in the semiconductor integrated circuit ENC which ismountable on the drive recorder according to the embodiment 1 of thepresent invention shown in FIG. 1, the above-mentioned coordinatetransform of all the pixels from the intermediate part Lm of the imagewhich is the second partial image of the captured image into theperipheral part Lp of the image which is the third partial image isautomatically performed by the pixel enlargement/reduction unit 64 whichresponds to the vehicle speed information of the vehicle speedmeasurement unit.

<<Enlargement of Object Size>>

On the other hand, it is necessary to enlarge the size of the thirdobject C of the subject as an object of the reference image included inthe central part Lc of the image which is the first partial image of thecaptured image of FIG. 3 in order to perform image compression of thethird object C of the subject moving to the intermediate part Lm of theimage which is the second partial image of FIG. 4 with a high imagecompression rate.

FIG. 5 is an explanatory diagram of a hierarchical structure to a blockfrom a sequence of an encoding process by the video encoding processperformed by the semiconductor integrated circuit ENC which is mountableon the drive recorder according to the embodiment 1 of the presentinvention shown in FIG. 1.

Here, the hierarchical structure from the sequence to the block shown inFIG. 5 is completely identical to the hierarchical structure in the MPEGvideo encoding.

As shown in FIG. 5, the hierarchical structure from the sequence to theblock has a six-tier structure from a Sequence 100 which corresponds tothe entire video to Blocks 150, 160 and 170 which are process units ofdiscrete cosine transform (DCT).

In other words, the first tier is the Sequence 100, the second tier is agroup of picture (GOP) 110, the third tier is a Picture 120, the fourthtier is a Slice 130, the fifth tier is a Macro-block 140, and the sixthtier is Blocks 150, 160 and 170. The number of Pictures 120 included inthe group of picture (GOP) 110, or the number of Macro-blocks 140included in the Slice 130 is relatively flexible.

As shown in FIG. 5, the Macro-block 140 includes four 8×8 pixelluminance signal blocks 150 which indicate a luminance signal component(Y), one 8×8 pixel blue color-difference signal block 160 whichindicates a blue color-difference signal (Cb=B−Y), and one 8×8 pixel redcolor-difference signal block 170 which indicates a red color-differencesignal (Cr=R−Y).

The process with regard to the motion vector MV of the motion predictionunit 2 and the motion compensation unit 4 of the semiconductorintegrated circuit ENC which is mountable on the drive recorderaccording to the embodiment 1 of the present invention shown in FIG. 1is processed for each macro block 140 shown in FIG. 5. Furthermore, thediscrete cosine transform unit 51 of the residual encoding unit 5 andthe inverse discrete cosine transform unit 61 of the local decoding unit6 of the semiconductor integrated circuit ENC both of which aremountable on the drive recorder according to the embodiment 1 of thepresent invention shown in FIG. 1, process any of one 8×8 pixelluminance signal block 150, one 8×8 pixel blue color-difference signalblock 160, and one 8×8 pixel red color-difference signal block 170 as aunit.

On the other hand, the size of the third object C of the subjectincluded in the central part Lc of the image which is the first partialimage of the captured image of FIG. 3 is enlarged, on a pixel-by-pixelbasis, by the pixel enlargement/reduction unit 64 of the local decodingunit 6 included in the semiconductor integrated circuit ENC according tothe embodiment 1 of the present invention of FIG. 1 in order to performimage compression on the third object C of the subject moving to theintermediate part Lm of the image which is the second partial image ofFIG. 4 with a high image compression rate.

FIG. 6 illustrates how the size of an object of a subject is enlargedand reduced on a pixel-by-pixel basis by a pixel enlargement/reductionunit 64 of a local decoding unit 6 of the semiconductor integratedcircuit ENC which is mountable on the drive recorder according to theembodiment 1 of the present invention shown in FIG. 1

FIG. 6 illustrates an object 600 of a small subject existing in thecentral part Lc of the image which is the first partial image of FIG. 3,and an object 601 of a large subject existing in the intermediate partLm of the image which is the second partial image of FIG. 3 or theperipheral part Lp of the image which is the third partial image.

First, when enlarging the object size from the object 600 of the smallsubject to the object 601 of the large subject, a pixelenlargement/interpolation process A_(EN) is performed by the pixelenlargement/reduction unit 64. In other words, the pixelenlargement/reduction unit 64 performs a pixel enlargement process fromthe object 600 of a small 4×4 pixel subject to the object 601 of a large8×8 pixel subject, for example, by the pixel enlargement/interpolationprocess A_(EN). In the pixel enlargement process, one pixel included inthe object 600 of the small subject is interpolated in a plurality ofpixels, for example 2×2 pixels, of the object 601 of the large subject.The enlargement factor and the interpolation factor in the pixelenlargement/interpolation process A_(EN) by the pixelenlargement/reduction unit 64 are determined by the vehicle speedinformation from the vehicle speed measurement unit such as aspeedometer of an automobile or the like supplied to the pixelenlargement/reduction unit 64.

Next, when reducing the object size from the object 601 of the largesubject to the object 600 of the small subject, a pixelreduction/thinning process A_(RED) is performed by the pixelenlargement/reduction unit 64. In other words, the pixelenlargement/reduction unit 64 performs a pixel reduction process fromthe object 601 of a large 8×8 pixel subject to the object 600 of a small4×4 pixel subject, for example, by the pixel reduction/thinning processA_(RED). In the pixel reduction process, a plurality of pixels, forexample 2×2 pixels of the object 601 of the large subject are thinned toone pixel included in the object 600 of the small subject. The reductionrate and the thinning rate in the pixel reduction/thinning processA_(RED) by the pixel enlargement/reduction unit 64 are determined by thevehicle speed information from the vehicle speed measurement unit suchas a speedometer of an automobile or the like supplied to the pixelenlargement/reduction unit 64.

<<Effect by the Embodiment 1 of the Present Invention>>

In the semiconductor integrated circuit ENC according to the embodiment1 of the present invention which is mountable on the drive recorderdescribed above referring to FIGS. 1 to 6, the captured image is dividedinto the first partial image which is the small-sized central part Lc ofthe captured image and the second partial image which is theintermediate part Lm of the large-sized image around thereof. The sizeenlargement factor from the small-sized first partial image which is thecentral part Lc of the image to the large-sized second partial imagewhich is the intermediate part Lm of the image is determined by thevehicle speed information from the vehicle speed measurement unit suchas a speedometer of an automobile or the like supplied to the pixelenlargement/reduction unit 64.

On addition, the pixel coordinate transform and the pixelenlargement/interpolation process required in that occasion areautomatically performed by the pixel enlargement/reduction unit 64 whichresponds to the vehicle speed information from the vehicle speedmeasurement unit. In that occasion, the processing load and powerconsumption of the semiconductor integrated circuit ENC according to theembodiment 1 of the invention can be reduced, since the characteristicpoint extraction process described in the patent document 1 forextracting edges, particular straight lines and curves, particularshapes, or regions having particular colors can be omitted.

Embodiment 2 Configuration of Another Semiconductor Integrated Circuit

FIG. 7 illustrates a configuration of another semiconductor integratedcircuit ENC which is mountable on the drive recorder according to anembodiment 2 of the present invention.

The semiconductor integrated circuit ENC according to the embodiment 2of the present invention shown in FIG. 7 differs from the semiconductorintegrated circuit ENC according to the embodiment 1 of the inventionshown in FIG. 1 as follows.

That is, the semiconductor integrated circuit ENC according to theembodiment 2 of the present invention shown in FIG. 7 includes abackground image encoding unit B-ENC for processing a image (backgroundimage) of all the stationary subjects moving from generally the centerof the image toward the peripheral part of the image, an moving objectimage encoding unit OB-ENC for processing moving objects such asoncoming vehicles and passing vehicles, an image synthesizing unit 9-1,a first image generating unit 9-2 and a second image generating unit9-3.

The background image encoding unit B-ENC of the semiconductor integratedcircuit ENC according to the embodiment 2 of the present invention shownin FIG. 7 includes, in an exactly similar manner as the semiconductorintegrated circuit ENC shown in FIG. 1, the first frame memory 1, themotion prediction unit 2, the subtraction unit 3, the motioncompensation unit 4, the residual encoding unit 5, the local decodingunit 6, the motion vector variable-length encoding unit 7, and thebuffer unit 8, the residual encoding unit 5 including the discretecosine transform unit (DCT) 51, the quantization unit (Q) 52, and theresidual variable-length encoding unit 53, the local decoding unit 6including the inverse quantization unit (IQ) 61, the inverse discretecosine transform unit (IDCT) 62, the addition unit (+) 63, the pixelenlargement/reduction unit 64, and the second frame memory 65.Therefore, since the configuration and operation of the background imageencoding unit B-ENC of the semiconductor integrated circuit ENCaccording to the embodiment 2 of the present invention shown in FIG. 7is exactly identical to the configuration and the operation of thesemiconductor integrated circuit ENC shown in FIG. 1, detaileddescription of the operation of the background image encoding unit B-ENCis omitted here. However, a video compression bit stream of the image(background image) of all the stationary subjects moving from the centerof the image toward the peripheral part of the image is generated fromthe output terminal of the buffer unit 8 and supplied to the inputterminal of the first image generating unit 9-2, and image data isgenerated from the output terminal of the first image generating unit9-2 and supplied to one input terminal of the image synthesizing unit9-1.

The moving object image encoding unit OB-ENC of the semiconductorintegrated circuit ENC according to the embodiment 2 of the presentinvention shown in FIG. 7 for processing moving objects such as oncomingvehicles and passing vehicles includes, exactly in a similar manner asthe background image encoding unit B-ENC, a first frame memory 11, amotion prediction unit 12, a subtraction unit 13, a motion compensationunit 14, a residual encoding unit 15, a local decoding unit 16, a motionvector variable-length encoding unit 17, and a buffer unit 18, theresidual encoding unit 15 including a discrete cosine transform unit(DCT) 151, a quantization unit (Q) 152, and a residual variable-lengthencoding unit 153, the local decoding unit 16 including an inversequantization unit (IQ) 161, an inverse discrete cosine transform unit(IQ) 162, an addition unit (+) 163, a pixel enlargement/reduction unit164, and a second frame memory 165.

The video signal Video_in from the vehicle front camera which capturesvideo images in front of the vehicle such as an automobile is suppliedto the first frame memory 11 of the moving object image encoding unitOB-ENC.

The motion prediction unit 12 generates a motion vector MV only foroncoming or passing vehicles from the video signal Video_in stored inthe first frame memory 11, and the motion vector MV of the oncoming orpassing vehicles is supplied to the motion compensation unit 14 and thevector variable-length encoding unit 17.

Since the moving speed of an oncoming vehicle is faster than the movingspeed of a stationary subject moving from generally the center of theimage toward the peripheral part of the image, it is possible todistinguish the movement of the oncoming car from the movement of thestationary subject. Since a passing vehicle moves from the peripheralpart of the image toward the center of the image whereas the stationarysubject moves from generally the center of the image toward theperipheral part of the image, it is possible to distinguish the movementof the passing vehicle from the movement of the stationary subject. Inthis manner, the motion prediction unit 12 generates the motion vectorMV only for the oncoming or passing vehicles and supplies it to themotion compensation unit 14 and the vector variable-length encoding unit17, while supplying an object moving speed only for the speed of theoncoming vehicle and the speed of the passing vehicle to the pixelenlargement/reduction unit 164.

As a result, the pixel enlargement/reduction unit 164 forms a referenceimage of the oncoming vehicle by performing the pixel enlargementprocessing responding to the oncoming vehicle speed with regard to theobject of the oncoming vehicle and stores it in the second frame memory165, while forming a reference image of the passing vehicle byperforming the pixel reduction processing responding to the passingvehicle speed with regard to the object of the passing vehicle andstoring it in the second frame memory 165. Therefore, the motioncompensation unit 14 generates a motion compensation prediction signalonly for the oncoming or passing vehicles from the reference image ofthe oncoming or passing vehicles stored in the second frame memory 165,and from the motion vector MV of the oncoming or passing vehiclessupplied from the motion prediction unit 2. Since the video signal beingread from the first frame memory 11 according to the encoding order issupplied to one input terminal of the subtraction unit 13 while themotion compensation prediction signal only for the oncoming or passingvehicles is supplied from the motion compensation unit 14 to the otherinput terminal of the subtraction unit 13, a predicted residual only forthe oncoming or passing vehicles generated from the output ofsubtraction unit 13 is supplied to the residual encoding unit 15. Sinceno compensation prediction signal is supplied from the motioncompensation unit 14 to the other input terminal of subtraction unit 13with regard to a stationary subject other than the oncoming or passingvehicles, the predicted residual with regard to the stationary subjectis ignored because the output of the subtraction unit 13 with regard tothe stationary subject is saturated to the maximum output. Therefore,the predicted residual only for the oncoming or passing vehicles fromthe output of subtraction unit 13 is quantized by the quantization unit(Q) 152 after having been subjected to discrete cosine transform whichis an orthogonal transform by the discrete cosine transform unit (DCT)151. The quantized residual signal only for the oncoming vehicle and thepassing vehicle from the quantization unit (Q) 152 of the residualencoding unit 15 is encoded by the residual variable-length encodingunit 153, and the residual variable-length encoding signal only for theoncoming or passing vehicles generated from the residual variable-lengthencoding unit 153 is supplied to one input terminal of the buffer unit18. In addition, the motion vector MV of the oncoming or passingvehicles generated from the motion prediction unit 12 is supplied to themotion vector variable-length encoding unit 17 so that a motion vectorvariable-length encoded signal only for the oncoming or passing vehiclesis generated from the motion vector variable-length encoding unit 17 andsupplied to the other input terminal of the buffer unit 18. Therefore, avideo compression bit stream only for the oncoming or passing vehiclesis generated from the output terminal of the buffer unit 18 and suppliedto the input terminal of the second image generating unit 9-3, and imagedata is generated from the output terminal of the second imagegenerating unit 9-3 and supplied to the other input terminal of theimage synthesizing unit 9-1.

The image synthesizing unit 9-1, including an alpha blend imageprocessing unit, for example, has a function of image-synthesizingbackground video data of the video compression bit stream of the imageof a stationary subject (background image) supplied from the outputterminal of the buffer unit 8 of the background image encoding unitB-ENC and moving object video data of the video compression bit streamonly for the oncoming or passing vehicles supplied from the outputterminal of the buffer unit 18 of the moving object image encoding unitOB-ENC. Therefore, an image composition video signal including thebackground video data and the moving object video data of the oncomingor passing vehicles from the image synthesizing unit 9-1 is generated,and recorded on a vehicle-mounted recording medium including for examplea hard disk drive (HDD) or a semiconductor nonvolatile memory, which arenot shown in FIG. 7.

FIG. 8 illustrates how an image of a stationary subject (backgroundimage) is captured, together with an oncoming vehicle and a passingvehicle, when capturing video images in front of the vehicle by thevehicle front camera of the drive recorder having mounted thereon thesemiconductor integrated circuit ENC according to the embodiment 2 ofthe present invention shown in FIG. 7.

In FIG. 8, an image of not only the high-rise building on the left-handside of the road as with FIG. 2, but also an oncoming vehicle and apassing vehicle is captured on the right-hand side of the road. Althoughthe oncoming vehicle on the right-hand side of the road is a small-sizedobject Copp_c in the central part Lc of the image, it turns into alarge-sized object Copp_p in the peripheral part Lp of the image.Although the passing vehicle on the right-hand side of the road is alarge-sized object Cpass_p in the peripheral part Lp of the image, itturns into a small-sized object Cpass_c in the central part Lc of theimage.

<<Effect by the Embodiment 2 of the Present Invention>>

In the semiconductor integrated circuit ENC according to the embodiment1 of the present invention which is mountable on the drive recorderdescribed above referring to FIGS. 7 and 8, the pixelenlargement/reduction unit 164 can form a reference image of an oncomingvehicle by performing the pixel enlargement processing in response tothe oncoming vehicle speed with regard to the object of the oncomingvehicle and store it in the second frame memory 165, while forming areference image of a passing vehicle by performing the pixel reductionprocessing in response to the passing vehicle speed with regard to theobject of the passing vehicle and storing it in the second frame memory165.

Therefore, according to the embodiment 2 of the present invention, imagecompression with a high compression rate and image recording with a highimage precision are facilitated with regard to oncoming or passingvehicles. Accordingly, it becomes possible, when an accident occurs withdriving error of either an oncoming vehicle or a passing vehicle beingthe main accident cause, to record clearly the driving situation of theoncoming vehicle or the passing vehicle which caused the accident in thedrive recorder.

Although the invention made by the inventors has been specificallydescribed based on various embodiments, it is needless to say that theinvention is not limited thereto and various modification can be madewithout deviating from the spirit of the invention.

For example, in the embodiment 1 and the embodiment 2 of the presentinvention, it is possible to detect the steering angle of the wheel of avehicle due to steering action associated with driving of the vehiclesuch as an automobile by a steering angle detector mounted on thevehicle, and compensate the image of a stationary subject (backgroundimage) or the moving speed of oncoming or passing vehicles using thedetected steering angle. It is also possible on the occasion tocompensate the image of a stationary subject (background image), or thedirection or inclination of the object of the oncoming or passingvehicles.

Furthermore, the vehicle having the drive recorder according to thepresent invention mounted thereon is not limited to automobiles usingthe driving force of an internal combustion engine which burns oil fuelsuch as gasoline or light oil. It is needless to say that the driverecorder according to the present invention can also be mounted on anelectric vehicle using the driving force of a battery-driven electricmotor, or a hybrid car employing both an internal combustion engine andan electric motor.

Moreover, the present invention is not limited to a drive recordermounted on a vehicle such as an automobile. The present invention isalso applicable to an auto-zoom mechanism in which the object lensquickly moves in a forward or backward direction of the subject by abattery-driven motor following the camera work of the video camera bythe photographer. In other words, the pixel enlargement/reduction unit64 calculates, in response to the number of rotations of thebattery-driven motor corresponding to the moving speed of the focus ofthe object lens, the amount of movement of pixels due to coordinatetransform of pixels from intermediate part of the image toward theperipheral part of the image or the amount of movement of pixels due tocoordinate transform of pixels from the peripheral part of the imagetoward the intermediate part of the image, and the enlargement factor ofthe objects of the subjects moving from the intermediate part of theimage toward the peripheral part of the image or the reduction rate ofthe objects of the subjects moving from the peripheral part of the imagetoward the intermediate part of the image.

What is claimed is:
 1. A semiconductor integrated circuit including avideo encoder comprising a motion prediction unit, a motion compensationunit, a subtraction unit, a discrete cosine transform unit, aquantization unit, an inverse quantization unit, an inverse discretecosine transform unit, and an addition unit, wherein: the motionprediction unit generates, in response to a video signal from a camera,a motion vector from the video signal, and the motion prediction unitsupplies the motion vector to one input of the motion compensation unitso that, the video signal from the camera can be supplied to one inputof the subtraction unit, an output of the subtraction unit can besupplied to an input of the discrete cosine transform unit, an output ofthe discrete cosine transform unit can be supplied to an input of thequantization unit, an output of the quantization unit can be supplied toan input of the inverse quantization unit, an output of the inversequantization unit can be supplied to an input of the inverse discretecosine transform unit, an output of the inverse discrete cosinetransform unit can be supplied to one input of the addition unit, areference image of an output of the addition unit can be supplied to theother input of the motion compensation unit, and a motion compensationprediction signal of an output of the motion compensation unit can besupplied to the other input of the subtraction unit and the other inputof the addition unit; and the video encoder divides the video signalfrom the camera into a plurality of partial images including the centralpart of the image and the peripheral part of the image according to thedistance from the center of the image, and processes the partial images,the video encoder further comprises a pixel processing unit connectedbetween the output of the addition unit and the other input of themotion compensation unit, the pixel processing unitcoordinate-transforms coordinates of a pixel included in the centralpart of the image in the reference image of the output of the additionunit into coordinates of the peripheral part of the image, and the pixelprocessing unit performs a process of enlarging an object of a subjectincluded in the central part of the image on a pixel-by-pixel basis whenperforming the coordinate transform, wherein the pixel processing unitresponds to speed information to provide compression of the image. 2.The semiconductor integrated circuit according to claim 1, wherein thecamera is a vehicle front camera which captures video images in front ofthe vehicle, and an amount of movement of the pixel due to thecoordinate transform of the pixel from the central part of the imagetoward the peripheral part of the image, and an enlargement factor ofthe object of the subject moving from the central part of the image tothe peripheral part of the image are calculated by the pixel processingunit which responds to the speed information comprising vehicle speedinformation from a vehicle speed measurement unit mounted on the vehicleto provide the compression of the image.
 3. The semiconductor integratedcircuit according to claim 2, wherein the video encoder divides thevideo signal from the camera into the central part of the image, theperipheral part of the image, and an intermediate part of the imagebetween the central part and the peripheral part, and processes therespective parts.
 4. The semiconductor integrated circuit according toclaim 3, wherein the video encoder further comprises: a first memoryconnected to the one input of the subtraction unit and the input of themotion prediction unit to store the video signal from the camera; and asecond memory connected between the output of the pixel processing unitand the other input of the motion compensation unit to store an outputimage signal of the pixel processing unit.
 5. The semiconductorintegrated circuit according to claim 4, wherein the video encoderfurther comprises a first variable-length encoding unit, a secondvariable-length encoding unit, and a buffer unit, and wherein the outputof the quantization unit can be supplied to an input of the firstvariable-length encoding unit, and the motion vector generated by themotion prediction unit can be supplied to an input of the secondvariable-length encoding unit; and further comprising an output of thefirst variable-length encoding unit and an output of the secondvariable-length encoding unit can be supplied to one input and the otherinput of the buffer unit, respectively, and an output of the buffer unitcan be recorded on a recording medium.
 6. The semiconductor integratedcircuit according to claim 4, wherein: the video encoder includes afirst video encoder and a second video encoder, the first video encoderprocesses an object of a stationary subject, which is the subject movingfrom the central part of the image toward the peripheral part of theimage, and the second video encoder processes an object of a movingsubject, which is the subject moving from the central part of the imagetoward the peripheral part of the image.
 7. The semiconductor integratedcircuit according to claim 4, further comprising an image synthesizingunit which synthesizes a first video encoded signal generated by thefirst video encoder and a second video encoded signal generated by thesecond video encoder.
 8. The semiconductor integrated circuit accordingto claim 7, wherein an output of the image synthesizing unit isrecordable on a recording medium.
 9. The semiconductor integratedcircuit according to claim 1, wherein the video encoder furthercomprises: a first memory connected to the one input of the subtractionunit and the input of the motion prediction unit to store the videosignal from the camera; and a second memory connected between the outputof the pixel processing unit and the other input of the motioncompensation unit to store an output image signal of the pixelprocessing unit.
 10. The semiconductor integrated circuit according toclaim 1, further comprising a memory unit that separately stores thevideo signal from the camera in a separate memory area than an outputimage signal of the pixel processing unit.
 11. The semiconductorintegrated circuit according to claim 1, further comprising: a memory tostore an output image signal of the pixel processing unit, the memorybeing accessible by the motion compensation unit, wherein the pixelprocessing unit transforms coordinates of a pixel included in a centralreference image to coordinates of a peripheral part of the image inorder to move the central reference image toward a peripheral part ofthe image, and wherein the pixel processing unit coordinate-transformscoordinates of a pixel included in the central part of the image in thereference image of the output of the addition unit into coordinates ofthe peripheral part of the image to perform compression of the imageaccording to the speed information.
 12. A method of operating asemiconductor integrated circuit including a video encoder comprising amotion prediction unit, a motion compensation unit, a subtraction unit,a discrete cosine transform unit, a quantization unit, an inversequantization unit, an inverse discrete cosine transform unit, and anaddition unit, the method comprising: generating, by the motionprediction unit, in response to a video signal from a camera, a motionvector from the video signal, and the motion prediction region suppliesthe motion vector to one input of the motion compensation unit so that,the video signal from the camera can be supplied to one input of thesubtraction unit, an output of the subtraction unit can be supplied toan input of the discrete cosine transform unit, an output of thediscrete cosine transform unit can be supplied to an input of thequantization unit, an output of the quantization unit can be supplied toan input of the inverse quantization unit, an output of the inversequantization unit can be supplied to an input of the inverse discretecosine transform unit, an output of the inverse discrete cosinetransform unit can be supplied to one input of the addition unit, areference image of an output of the addition unit can be supplied to theother input of the motion compensation unit, and a motion compensationprediction signal of an output of the motion compensation unit can besupplied to the other input of the subtraction unit and the other inputof the addition unit; and dividing, by the video encoder, the videosignal from the camera into a plurality of partial images including thecentral part of the image and the peripheral part of the image accordingto the distance from the center of the image, and processes the partialimages, wherein the video encoder further comprises a pixel processingunit connected between the output of the addition unit and the otherinput of the motion compensation unit, wherein the pixel processing unitcoordinate-transforms coordinates of a pixel included in the centralpart of the image in the reference image of the output of the additionunit into coordinates of the peripheral part of the image; andperforming, by the pixel processing unit, a process of enlarging anobject of a subject included in the central part of the image on apixel-by-pixel basis when performing the coordinate transform, whereinthe pixel processing unit responds to speed information to providecompression of the image.
 13. The method of operating a semiconductorintegrated circuit according to claim 12, wherein: the camera is avehicle front camera which captures video images in front of thevehicle, and an amount of movement of the pixel due to the coordinatetransform of the pixel from the central part of the image toward theperipheral part of the image, and an enlargement factor of the object ofthe subject moving from the central part of the image to the peripheralpart of the image are calculated by the pixel processing unit whichresponds to the speed information comprising vehicle speed informationfrom a vehicle speed measurement unit mounted on the vehicle to providethe compression of the image.
 14. The method of operating asemiconductor integrated circuit according to claim 13, wherein thevideo encoder divides the video signal from the camera into the centralpart of the image, the peripheral part of the image, and an intermediatepart of the image between the central part and the peripheral part, andprocesses the respective parts.
 15. The method of operating asemiconductor integrated circuit according to claim 14, wherein thevideo encoder further comprises: a first memory connected to the oneinput of the subtraction unit and the input of the motion predictionunit to store the video signal from the camera; and a second memoryconnected between the output of the pixel processing unit and the otherinput of the motion compensation unit to store an output image signal ofthe pixel processing unit.
 16. The method of operating a semiconductorintegrated circuit according to claim 15, wherein: the video encoderfurther comprises a first variable-length encoding unit, a secondvariable-length encoding unit, and a buffer unit, and wherein the outputof the quantization unit can be supplied to an input of the firstvariable-length encoding unit, and the motion vector generated by themotion prediction unit can be supplied to an input of the secondvariable-length encoding unit, and an output of the firstvariable-length encoding unit and an output of the secondvariable-length encoding unit can be supplied to one input and the otherinput of the buffer unit, respectively, and an output of the buffer unitcan be recorded on a recording medium.
 17. The method of operating asemiconductor integrated circuit according to claim 15, wherein: thevideo encoder includes a first video encoder and a second video encoder,the first video encoder processes an object of a stationary subject,which is the subject moving from the central part of the image towardthe peripheral part of the image, and the second video encoder processesan object of a moving subject, which is the subject moving from thecentral part of the image toward the peripheral part of the image. 18.The method of operating a semiconductor integrated circuit according toclaim 15, wherein the semiconductor integrated circuit further comprisesan image synthesizing unit which synthesizes a first video encodedsignal generated by the first video encoder and a second video encodedsignal generated by the second video encoder.
 19. The method ofoperating a semiconductor integrated circuit according to claim 18,wherein an output of the image synthesizing unit is recordable on arecording medium.
 20. A semiconductor integrated circuit, comprising: avideo encoder including: a motion prediction unit that generates, inresponse to a video signal from a camera, a motion vector from the videosignal; a motion compensation unit that receives from the motionprediction unit the motion vector so that, the video signal from thecamera that can be outputted; a subtraction unit that receives the videosignal from the output of the motion compensation unit; an addition unitreceiving an output of the subtraction unit, a reference image of anoutput of the addition unit can be supplied to the motion compensationunit, and a motion compensation prediction signal of an output of themotion compensation unit can be supplied to the subtraction unit and theaddition unit, wherein the video encoder divides the video signal fromthe camera into a plurality of partial images including the central partof the image and the peripheral part of the image according to thedistance from the center of the image, and processes the partial images,wherein the video encoder further comprises a pixel processing unitconnected between the output of the addition unit and the other input ofthe motion compensation unit, wherein the pixel processing unitcoordinate-transforms coordinates of a pixel included in the centralpart of the image in the reference image of the output of the additionunit into coordinates of the peripheral part of the image, and whereinthe pixel processing unit performs a process of enlarging an object of asubject included in the central part of the image on a pixel-by-pixelbasis when performing the coordinate transform, wherein the pixelprocessing unit responds to speed information to provide compression ofthe image.
 21. The semiconductor integrated circuit according to claim20, wherein the video encoder further comprises: a first memoryconnected to the one input of the subtraction unit and the input of themotion prediction unit to store the video signal from the camera; and asecond memory connected between the output of the pixel processing unitand the other input of the motion compensation unit to store an outputimage signal of the pixel processing unit.